The gunmen pulled in front of a police vehicle in an unmarked truck in the area's main city of El-Arish, before standing up on the truck bed and opening fire, the officials say. They then raised a black flag associated with jihadis and shouted "God is great."

Intelligence officials who declined to be named in line with regulations say the suspects then sped off.

The head of security in northern Sinai, Ahmed Bakr, confirmed that three policemen were killed in the Saturday attack.

Egyptian security forces have come under attack numerous times by militants in northern Sinai who have exploited the security void in the desert peninsula that borders the Gaza Strip and Israel.